The present disclosure relates to a fixing device fixing a toner image onto a recording medium and an image forming apparatus including the fixing device.
Conventionally, an electrographic image forming apparatus, such as a copying machine, a printer, a facsimile or alternatively a multifunction peripheral having functionally these, includes a fixing device fixing a toner image onto a recording medium. The fixing device includes a fixing member (e.g. a fixing roller or a fixing belt) and a pressuring member (e.g. a pressuring roller or a pressuring belt) and, between the fixing member and pressuring member, a fixing nip is formed. When the recording medium is passed though the fixing nip in a condition where the fixing member is heated by a heat source, such as a halogen heater, a toner image formed on a surface of the recording medium is heated and melted, and then, the toner image is fixed onto the recording medium.
Conventionally, in such a fixing device, the fixing member is composed of the fixing roller. However, recently, in viewpoints of energy saving and shortening of a warm-up time and a first print time, instead of the fixing roller, the fixing member is often composed of a thin member having a small heat capacity as the fixing belt.
In such a fixing device, when the fixing member having the small heat capacity is directly heated by the heat source, a problem of locally heating the fixing member to bring temperature non-uniformity onto the fixing member and to deform the fixing member is caused.
Thereupon, there is a configuration of heating a heat conducting member by radiant heat emitted from the heat source and heating the fixing member by heat conduction from the heat conducting member. In such a conventional technique, the radiant heat emitted from the heat source is reflected by a reflecting member toward the heat conducting member.
In the conventional technique as mentioned above, there is a case where both end parts of the heat conducting member are fixed to both end parts of the reflecting member. In this case, the heat conducting member and reflecting member always come into contact with each other. Because of this, when the fixing member is heated by the heat conduction from the heat conducting member, not only heat transfer from the heat conducting member to the fixing member, but also heat transfer from the heat conducting member to the reflecting member is caused, and then, it is difficult to efficiently heat the fixing member.
Moreover, in the conventional technique as mentioned above, there is a case where the heat conducting member and reflecting member are connected via a reinforcement member. In this case, if uniformity of the temperature of the fixing member is desired, since it is impossible to efficiently transfer the heat of the fixing member to the reflecting member via the heat conducting member, a time required for uniformizing the temperature of the fixing member is elongated.